The structure and diversity of the bacterial community in the overlying water of the Yangzong Lake in Yunnan

Bacteria are critical components of lake ecosystems, and understanding the characteristics of bacterial community structure and diversity indices is of significant importance for the analysis and management of lake ecology. In this study, overlying water samples were collected from Yangzong Lake in May, June, and July 2021. High-throughput sequencing and statistical analysis were employed to investigate the relationships between physicochemical factors, bacterial community structure, and diversity in the overlying water of Yangzong Lake. The results showed significant differences in oxidation-reduction potential among the sampling points. The order of oxidation-reduction potential was as follows: Yangzong DAHE > Yangzong Lake South > Yangzong Lake Middle > Yangzong Lake North, while other physicochemical factors exhibited minor differences. The number of OTUs and bacterial alpha diversity index in the overlying water of Yangzong Lake Middle were higher than those in Yangzong Lake North, Yangzong Lake South, and Yangzong DAHE. The dominant bacterial phyla in the overlying water were Actinobacteriota, Bacteroidota, and Proteobacteria. Actinobacteriota had the highest relative abundance of 34.63% in Yangzong Lake North, while Bacteroidota had the highest relative abundance of 33.79% in Yangzong Lake South, and Proteobacteria had the highest relative abundance of 27.29% in Yangzong Lake Middle. The dominant genera were hgcI_clade, CL500-29_marine_group, and Flavobacterium. Among them, hgcI_clade had the highest relative abundance of 37.56% in Yangzong Lake North, CL500-29_marine_group had the highest relative abundance of 35.22% in Yangzong Lake South, and Flavobacterium had the highest relative abundance of 42.02% in Yangzong Lake Middle. Correlation analysis revealed significant correlations between Campilobacterota at the phylum level and dissolved oxygen (DO) and total phosphorus (TP). At the genus level, Flavobacterium, Limnohabitans, and Pseudarcicella showed significant correlations with DO and TP.